Decarbonizing hard-to-abate sectors is critical to achieve climate change goals given the unique and often fossil fuel-based manufacturing processes. For developed and emerging economies, evaluating power and heavy industry sectors are pertinent given the immense growth expected in the upcoming decades. This presentation will focus on cost and emission models that have been developed and evaluated using the Sesame platform. Specifically, case studies for Hydrogen, Iron and Steel, and Power will be presented demonstrating the impact of technology options, supply chain choices and regional differences. In addition to the plant-level analysis, a system view will be taken to estimate emissions and energy consumption for the entire fleet. By comparing the various technology routes on a cost and emission basis, potential decarbonization strategies, marginal abatement cost, and sensitivities to fuel and other operational costs will be analyzed. The sectoral analysis indicates the immense increase in energy consumption and corresponding infrastructure support for industrial decarbonization. A combination of resource efficiency and technology improvements will be important for reducing emissions from a business-as-usual operation. Overall, the analysis indicates the role of system analysis in evaluating plant-level and system level changes in legacy sectors that are expanding and will be transitioning from traditional production methods. This study is timely as the global community sets climate goals and must consider hard-to-abate sectors, during the energy transition. Using system analysis provides insight to future plant-level and sectoral-level emission and cost challenges.